KRAFT LAW & CONSULTANCY
Interest Calculator
Every period, a clear breakdown.
Choose the principal, the date range and the type of interest. See the rate changes, day counts and interest for each period, with their legal basis.
See your interest
period by period.
The principal, the total interest and a sourced breakdown by period will appear here.
Method of calculation and scope
For each period, principal × annual rate / 100 × days / 365 is calculated. The denominator is 365 in leap years too; 29 February is included in the day count. This method is a stated calculation convention; a different convention in a contract or adopted by a court should be assessed separately. Interest for a period is not added to the principal.
Statutory interest changed to 24% on 1 June 2024. From 31 July 2026, 80% of the rediscount rate at the end of the previous year is used as the basis. If the rediscount rate on 30 June differs from the year-end rate by at least 5 percentage points, 80% of the 30 June rate is used for the second half of the year. For this last period of 2026, the calculated statutory rate is 31%.
For commercial default interest, the advance rate at the end of the previous year is used as the basis; if there is a difference of at least 5 percentage points on 30 June, the new reference is used for the second half of the year. It is compared with the statutory rate. Not every change the Central Bank of the Republic of Türkiye makes during the year starts a new default interest period by itself.
Which situations need a separate review?
What should I do if the contract provides for interest?
The contractual and default rates, TCO arts. 88 and 120, the nature of the commercial transaction and any special rules must be assessed together. Where no default rate has been agreed, a higher contractual interest rate can change the outcome. The automatic calculation is therefore stopped; the own-rate option provides an arithmetical calculation without confirming legal validity.
Why are non-contractual debts not calculated automatically?
The Constitutional Court decision (Docket No. 2024/24, Decision No. 2025/164) and the effect in time of the later legislation must be examined for the specific debt. The tool does not make this legal choice on its own.
Can part payments or other types of interest be calculated?
Part payments and set-off, a changing principal, foreign currency, the highest deposit interest rate, public receivables, loan/card interest, compound interest and the supply of goods and services under art. 1530 of the Turkish Commercial Code are outside this version. The commercial default interest option is for art. 2(2) of Act No. 3095.
Is the data live?
No. Last checked: 7 November 2026. This version calculates from 1 January 2024 up to the date of that check. No estimated rate is used for earlier or later dates. The result is not a definitive determination of the claim or of default.
Official sources: Act No. 3095 (in Turkish) · Decision No. 8485 (in Turkish) · Act No. 7589, arts. 10 and 26 (in Turkish) · Central Bank rediscount and advance rate table (in Turkish) · TCO (in Turkish) · Constitutional Court decision (in Turkish).